Skeleton/Transcript
Transcript Text reads: The Mysteries of Life with Tim & Moby. The video shows Tim holding a letter. Tim reads it. TIM: Dear Tim and Moby, why is my head so hard? Thanks, Jove212. Hey there. Your head is hard because of your skull. The video changes to show Tim and Moby standing side by side in front of bookshelves in a biology lab. Moby raises his arm in front of Tim, and an X-ray screen pops out of Moby's hand. The screen shows Tim's neck and skull in green. The skull moves as Tim speaks. TIM: Your skull is part of your skeleton, a framework of bones that supports and protects all your soft insides and that helps you move around. The video changes to show a human skeleton from the top of the skull to just above the knees. The label "skeleton" appears in the upper-left corner of the screen. The skeleton changes into a human silhouette that shows the human organs and blood vessels. TIM: Bones are made up of several layers. On the outside is a thin membrane called the periosteum. It can be found everywhere but the endpoints of long bones. The video shows a cross section of a bone. The video zooms in on the upper-left corner of the bone to show the thin outer layer. The layer flashes the color red, and the label "periosteum" appears in the upper-left corner of the screen. TIM: Below that is a thick layer of hard compact bone, which surrounds a layer of spongy bone. The second layer of the bone flashes red. The layer is about four times thicker than the outer layer, and it has tightly fitting circles throughout its pattern. The label "compact bone" appears on the left side of the screen. The third layer starts flashing red. The layer has a beige background with brown shapeless spots to represent the spongy nature of the layer. The label "spongy bone" appears in the lower-left side of the screen. TIM: Bones are actually hollow, making them light enough to let us move around easily. In the hollow of most bones is a jelly-like substance called marrow, which produces a lot of the body’s blood cells. The video zooms out to show a horizontal cross section of the bone. Then it zooms in again. The center of the bone is cylindrical, and the marrow is red. The label "marrow" appears on the upper-left side of the screen. TIM: Bones also store calcium, which is needed by your body’s nerve and muscle cells. The video returns to a surface view of the bone. MOBY: Beep. TIM: Yeah, bones are pretty important. And we’ve got a lot of them! The number of bones in a human skeleton actually depends on age. Babies are born with more bones than adults, because some of their bones aren't fully fused yet. The video shows a side view of a woman holding a baby. Their images turn into silhouettes, but the skulls are showing. The woman has a solid skull, while the baby's skull has several sections. TIM: Adults usually have 206 bones total. Each bone is adapted for a specific function: Like, a big, flat breastplate protects our heart and lungs, while small, delicate bones in our wrists and hands let us make precise movements. The video shows the human skeleton again. The camera zooms in on the chest to show the breastplate. The camera then moves down to show the delicate nature of the human hand. TIM: Our thick leg bones support our weight and provide power so we can move fast and carry heavy loads. The camera move again to show the skeleton from the upper thighs to just above the ankles. MOBY: Beep? TIM: Well, the spine isn't a single bone. It's actually made of 33 little ring-shaped bones called vertebrae, which are stacked on top of each other. The video shows, on the left of the screen, a side view of a human spine as the camera moves from the bottom of the spine to the top. When it reaches the top, a close-up view of the vertebrae appears on the right side. The label "vertebrae" appears. TIM: The curve of the spine provides your body with shock absorption; if it were straight, just walking around would be a jarring experience. The video changes to show a split screen. On the left is a side view of a human skeleton against a dark-green background walking with a springy vertical motion. On the right is a side view of a human skeleton against a light-green background walking rigidly. Red stars are emanating from the back of the spine. MOBY: Beep? TIM: Well, bones are connected to each other by tough tissues called ligaments. And they're attached to your muscles by equally-tough tissues called tendons. The video shows the skeletal view of the bones making up the upper arm and wrist. The muscles of the upper arm appear, and then tendons and ligaments appear. The label "ligaments" appears with a line pointing to the ligaments between the bones in the elbow joint. The label "tendons" appears with a line pointing to the tendon that connects the bicep to the bone at the elbow. TIM: Without them, your skeleton would just … fall apart. The video shows a human skeleton crumbling to the bottom of the screen. TIM: To protect against the wear and tear of moving around, the ends of the bones are padded with a rubbery substance called cartilage. The places that bones meet are called joints. Because muscles stretch across joints, your skeleton moves when the muscles expand and contract. The video returns to the skeletal view of the bones making up the upper arm, wrist, and elbow. The cartilage between the bones flashes red. The label "cartilage" appears in the top right corner of the screen, and the label "joints" appears in the lower-right corner of the screen. Muscles, tendons, and ligaments reappear on the upper arm. The arm bends up and down at the elbow, showing how the muscles expand and contract. TIM: And that's your skeleton: providing support, protection, and movement every day of your life! MOBY: Beep. TIM: What do you mean, that's a cheesy ending? MOBY: Beep! TIM: Well, I don't see you talking. Category:BrainPOP Transcripts Category:BrainPOP Health Transcripts